1. Field of the Invention
This invention generally relates to electrical switching devices such as power circuit breakers. One such device is a low voltage power circuit breaker. Such devices typically have a housing enclosing the electrical components, and a cover through which there can be access to a switch. The switch can be, in particular, a toggle type switch, and the cover can have a slot-like opening therein through which a toggle lever of the switch passes. Within the housing, there can also be various connection devices for connecting incoming and outgoing power lines, as well as various other switching devices or shunts. These auxiliary devices can be located in various chambers disposed about the toggle switch. Some of these various other devices can have metered settings which are adjustable to vary the functioning of the switching devices, and since the cover generally extends to cover these devices as well, the cover can have windows therein to enable the settings to be viewed without having to remove the cover. The cover may also have fastening devices for fastening a mechanical rotary actuator or even a motor drive thereto for actuating the toggle switch.
2. Background Information
On electrical switching devices with toggle activation, and in particular on low voltage power circuit breakers, the front of the breaker enclosure can be covered with a cover, which can have a slot-shaped opening for the toggle of the switching mechanism. On both lateral sides of the slot-shaped opening in the cover, there can be fastening devices for attaching the mechanical rotary actuator or a motor drive for operation of the toggle switch. As described above, the cover can also cover chambers for shunt releases and/or auxiliary switches, etc., which can be located around the toggle lever in the breaker enclosure.
Such covers are conventionally fastened to the breaker enclosure by means of screws. As such, switching devices typically require a comparatively complex and expensive assembly and installation process. In circumstances where the cover needs to be opened, e.g. to replace the shunt releases and/or auxiliary switches located next to the toggle lever in the breaker enclosure, the screws holding the cover in place must be completely removed. The cover and the screws would then have to be set down wherever there is space. In the event of an interruption in the installation activities, the cover and the screws could possibly be misplaced or moved, and thus could be lost. If installation work is being performed simultaneously on several switching devices located next to one another, it would also be very easy to mix up the covers of the devices, and therefore require additional time in replacing the covers as the covers would need to be sorted out to match the appropriate cover with the appropriate housing. In particular, a switching of covers generally must be avoided if the switching devices are of different designs and if certain messages and symbols appear on the covers which differ from one switching device to another.
On such covers which are screwed into place, a comparatively complex and expensive installation process is also generally necessary if, for example, a mechanical rotary actuator for the toggle lever is fastened to the cover and is to be replaced by a motor drive. The rotary actuator can, like the motor drive, be bolted partly directly to the switching device housing and partly to an installation plate or to the door of the breaker enclosure.